The object of this program is to develop and evaluate polyurethane elastomers for use as maxillofacial prostheses. Several commercially-available materials were tested and compared with materials currently being used for prostheses, and two promising systems were identified. One is a two-component commercially-available system, Calthane ND2300. Part A is an aliphatic diisocyanate-terminated prepolymer and Part B is a hydroxy-terminated polyester. The two components when mixed together with suitable antioxidants and UV stabilizers react to form an elastomer that has potential as a prosthetic material. The other system is a new polyurethane involving several commercially-available components. Isophorone, an aliphatic diisocyanate, and Polymeg, an aliphatic polyether diol, are combined to form a reactive prepolymer. This liquid prepolymer is converted to an elastomer by combining it with 1,4-butanediol as a chain extender, and 1,2,6-hexanetriol as a crosslinking agent. This aliphatic polyurethane exhibits exceptional mechanical properties. Properties such as tensile strength, hardness, modulus, and tear strength can be optimized by adjustment in the ratio of isocyanate to hydroxyl groups in the formulation. The addition of UV stabilizers has resulted in a polymer that retains most of its mechanical strength even after many hours of accelerated aging tests. Although clinical tests have not yet been performed, these two systems show promise as future maxillofacial materials.